This invention relates to fluid check valves in general, and in particular to valves used to check the free flow of fluid from a broken or damaged riser.
Surface irrigation systems often incorporate sprinkler heads mounted on "risers" some distance above the surface being irrigated to increase the size of the area irrigated. Risers are pipes or conduits, typically copper or PVC plastic, which extend from ground-level, or below ground-level, fluid distribution conduits for the purpose of communicating fluid from the distribution conduits to the respective sprinkler heads which terminate them.
While the use of riser mounted sprinkler heads has great advantage in extending the area covered, it has a very significant disadvantage in that risers are exposed. Typically risers are not supported or buttressed in any way other then by their own strength. A copper or PVC riser can be very easily broken resulting most often in an open outlet, the fluid in the riser being no longer restricted by the sprinkler head. This wastes water and causes erosion.
This problem is especially acute for farmers who irrigate many and/or large fields. One or more broken risers can go unnoticed for long periods of time resulting in a terrible waste of water, serious erosion, and crop damage.
This invention presents a device which will allow fluid to flow normally into a riser when the egress of fluid from the riser is suitably restricted, as by a sprinkler head, but will arrest the flow of fluid into the riser when the egress is not so restricted. Thus if a riser becomes damaged and allows the fluid to be released from it unrestricted, the check valve according to this invention will automatically close and prevent the undesirable consequences described above.
Other advantages and attributes of this invention will be discussed or will be readily discernible from a reading of the text hereinafter.